I eliminated all postgresql packages from my install in order to fit 6.1 on
my laptop's disk.  I later tried to install them with GnoRPM.  I got the
following errors:
"error: user postgres does not exist - using root"
"error: group postgres does not exist - using root"
This was in testing the postgresql-test package.  After 100 pairs of
errors, I assumed it was in an infinite loop and killed GnoRPM.  I found no
way to break out of the loop.  I had selected all postgres-related packages
at the same time.  This was on a fresh install off the CD (not even any
users configured, or hostname or network), and almost all other packages
were installed.  Other packages installed fine, and this package later
installed fine on its own.  I had not changed password configuration and
was using MD5 and shadow passwords.  The user existed in the password file.

--jh--